The invention relates to a method of selecting a RTP (Real Time Protocol) element in a dynamic multicast tree for a multimedia conference and a record medium recorded with a program for realizing the method that can be read by computers; and, in more particular to a method of selecting a RTP element in a dynamic multicast tree for distributing an overload applied to the root node of the dynamic multicast tree when terminals which are not connected to a dynamic multicast network want to join a grand conference, and a record medium recorded with a program for realizing the method that can be read by computers.
A multimedia conference is composed of small-sized core conference participants and grand conference participants.
The small-sized core conference participants join the conference according to a multimedia conference setup procedure via a packet network, and other participants receive video and voice signals of the small-sized core conference participants.
The grand conference participants join and exit from the conference at any time. In a current method, a multi-point controller (MC) multicasts a media stream to terminals, and the participants receive the media stream of the multimedia conference by means of a multicasting. Also, the terminals which are not connected to the multicast network can join the conference by using the muticast network such as a current multicast backBONE (MBONE) or by using a dynamic multicast tree.
However, there has been a problem that the root node is overloaded if the dynamic multicast tree is used and a number of new conference participants send messages for joining the conference to the root node at the beginning of a new conference.
Therefore, it is an object of the invention to provide a method of selecting a RTP element in a dynamic multicast tree for distributing an overload applied to the root node of the dynamic multicast tree and a record medium recorded with a program for realizing the method that can be read by a computer.
In accordance with an aspect of the present invention, there is provided a method of selecting a RTP element in a dynamic multicast tree applied to a RTP element system, the method comprising the steps of: (a) confirming in the RTP element if the RTP element is subscribed to the dynamic multicast tree that a new multimedia terminal wants to join; (b) if the RTP element is not subscribed to the dynamic multicast that the new multimedia terminal wants to join according to a result of the confirmation in the step (a), joining in the RTP element the root node of the dynamic multicast tree and then causing the new multimedia terminal to join the dynamic multicast tree of a multimedia conference system; and (c) if the RTP element is subscribed to the dynamic multicast that the new multimedia terminal wants to join according to a result of the confirmation in the step (a), causing the new multimedia terminal to join the dynamic multicast tree of the multimedia conference system.
In accordance with another aspect of the present invention, there is provided a record medium recorded with a program that can be read by a computer for realizing, in a RTP element system having a mass processor, the following functions of: (a) confirming in the RTP element if the RTP element is subscribed to the dynamic multicast tree that a new multimedia terminal wants to join; (b) if the RTP element is not subscribed to the dynamic multicast that the new multimedia terminal wants to join according to a result of the confirmation in the step (a), joining in the RTP element the root node of the dynamic multicast tree and then causing the new multimedia terminal to join the dynamic multicast tree of a multimedia conference system; and (c) if the RTP element is subscribed to the dynamic multicast that the new multimedia terminal wants to join according to a result of the confirmation in the step (a), causing the new multimedia terminal to join the dynamic multicast tree of the multimedia conference system.